Self-Levelling Compound Calculator
Work out exactly how many bags of floor leveller you need. Enter your room dimensions and pour depth — we’ll handle the maths and add a waste allowance.
Enter Room Details
Dimensions, pour depth, and product weight — we’ll calculate bags needed
For irregular rooms, split into rectangles and add the areas together.
Typical range: 3–6 mm finishing layer; up to 50 mm for deeper fills. Check your product’s datasheet.
Usually 20 kg or 25 kg
Per bag at 1 mm deep
Used to estimate total material cost
Material Estimate
Bags, volume, and cost for your floor
Enter your room dimensions, pour depth, and product details above, then click Calculate bags needed to see your full material estimate.
Choosing the right pour depth
The depth you pour directly determines how many bags you need. Pouring too thin leaves high spots; too thick wastes product and can crack. Always check your manufacturer’s minimum and maximum depths.
Most self-levelling compounds are designed for finishing layers of 3–6 mm. For deeper fills, use a floor-levelling screed or add aggregate to extend the compound.
| Depth | Use Case | Type |
|---|---|---|
| 2–3 mm | Skim coat over near-flat subfloor; minor imperfections only | Minimum |
| 3–6 mm | Standard finishing layer before LVT, tiles, or wood flooring | Standard |
| 6–15 mm | Moderate dips and transitions between floor heights | Standard |
| 15–50 mm | Deep fills, uneven concrete, building up to door threshold | Deep fill |
| 50 mm+ | Use floor screed instead — self-leveller is not suitable | Screed |
How to apply self-levelling compound
Prepare the subfloor
Sweep, vacuum, and degrease the floor. Fill any holes or cracks larger than 3 mm with repair mortar and allow to cure fully. A contaminated or cracked subfloor will cause the compound to fail.
Prime the surface
Apply a suitable primer — usually diluted SBR or a dedicated floor primer — and allow it to become tacky (typically 20–30 minutes). Priming prevents rapid moisture absorption that causes cracking.
Mix the compound
Add the powder to the correct amount of clean water (not the other way round). Mix with a paddle mixer for 2–3 minutes until lump-free. Work quickly — most compounds have a 20–30 minute working time.
Pour and spread
Pour from the furthest corner, working towards the door. Use a float or spreader to guide the compound — it will level itself. Break any air bubbles with a spiked roller.
Allow to cure before laying flooring
Light foot traffic is usually possible after 2–4 hours. Wait the full curing time (often 24 hours) before installing floor coverings. Check moisture levels with a hygrometer before laying moisture-sensitive floors.